import sys
from PyQt6.QtWidgets import QApplication, QMainWindow, QPushButton
from PyQt6.QtCore import QSize, Qt

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("My App")

        button = QPushButton("Press Me!")
        self.setCentralWidget(button)
        self.setFixedSize(QSize(400, 300))


app = QApplication(sys.argv)

window = MainWindow()
window.show()

app.exec()
